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Automated regression test method for scientific computing libraries:Illustration with SPHinXsys

Journal of Hydrodynamics 2024年第3期36卷 466-478页

作者： Bo zhang {1. zhang Xiangyu Hu TUM School of Engineering and Design Technical University of MunichMunichGermany

Scientific computing libraries,whether in-house or open-source,have witnessed enormous progress in both engineering and scientific ***,it is important to ensure that modifications to the source code,prompted by bug fixing or new feature development,do not compromise the accuracy and functionality that have been already validated and *** paper introduces a method for establishing and implementing an automatic regression test environment,using the open-source multi-physics library SPHinXsys as an illustrative ***,a reference database for each benchmark test is generated from observed data across multiple *** comprehensive database encapsulates the maximum variation range of metrics for different strategies,including the time-averaged,ensemble-averaged,and dynamic time warping *** accounts for uncertainties arising from parallel computing,particle relaxation,physical instabilities,and ***,new results obtained after source code modifications undergo testing based on a curve-similarity comparison against the reference *** the source code is updated,the regression test is automatically executed for all test cases,providing a comprehensive assessment of the validity of the current *** regression test environment has been successfully implemented in all dynamic test cases within SPHinXsys,including fluid dynamics,solid mechanics,fluid-structure interaction,thermal and mass diffusion,reaction-diffusion,and their multi-physics couplings,and demonstrates robust capabilities in testing different *** is noted that while the current test environment is built and implemented for a particular scientific computing library,its underlying principles are generic and can be easily adapted for use with other libraries,achieving equal effectiveness.

关键词： Scientific computing open-source library verification and validation regression test automatic test environment curve similarity comparison smoothed particle hydrodynamics

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Evolution Mechanism of Carbon Covalent Bond during Coal Activation Using Mixed Atmosphere of H_(2)O and CO_(2)

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Journal of Thermal Science 2024年第5期33卷 1961-1973页

作者： WANG Mingyue zhang Siyuan HAN Shaobo zhang chi REN Qiangqiang Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of chinese Academy of Sciences Beijing 100049China State Key Laboratory of Coal Conversion Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China

Adequate destruction of the aromatic structure in coal is key to further reducing the emission of *** this research,activation reactions of Shenmu coal powder were carried out in a vertical tube *** study investigated the evolution mechanism of carbon covalent bonds during the activation process by altering the ratio of H_(2)O to CO_(2)in the activation *** theoretical validation was conducted through density functional *** two gas molecules follow different pathways to increase the reactivity of ***_(2)mainly participates in the cross-linking reaction by intensifying branching,while H_(2)O and char have lower adsorption energy barriers and are more likely to generate oxygen-containing functional *** molecules partially compete for active sites in a mixed gas atmosphere,but there is a synergism between the two *** synergism can be attributed to two *** inclusion of H_(2)O mitigates the generation of five-membered rings to a limited extent,while concurrently enhances the development of oxygen-containing functional *** oxygen-containing functional groups can effectively diminish the adsorption energy barrier associated with the interaction between gas molecules and char,consequently leading to a reduction in the energy demand for subsequent bond cleavage.

关键词： activation reaction carbon structure char CO_(2)/H_(2)O atmosphere density functional theory

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Thermodynamic Performance Analysis of E/F/H-Class Gas Turbine Combined Cycle with Exhaust Gas Recirculation and Inlet/Variable Guide Vane Adjustment under Part-Load Conditions

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Journal of Thermal Science 2024年第1期33卷 348-367页

作者： LI Keying chi Jinling WANG Bo {1. Shijie Key Lab of Advanced Energy and Power Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of chinese Academy of Sciences Beijing 100049China School of Mechanical Electronic&Information Engineering China University of Mining&Technology-BeijingBeijing 100083China

Exhaust gas recirculation control(EGRC),an inlet air heating technology,can be utilized in combination with inlet/variable guide vane control(IGV/VGVC) and fuel flow control(FFC) to regulate the load,thereby effectively improving the part-load(i.e.,off-design) performance of the gas turbine combined cycle(GTCC).In this study,the E-,F-,and H-Class EGR-GTCC design and off-design system models were established and validated to perform a comparative analysis of the part-load performance under the EGR-IGV-FFC and conventional IGV-FFC strategies in the E/F/H-Class *** show that EGR-IGV-FFC has considerable potential for the part-load performance enhancement and can show a higher combined cycle efficiency than IGV-FFC in the E-,F-,and H-Class ***,the part-load performance improvement in the corresponding GTCC was weakened for the higher class of the gas turbine because of the narrower load range of EGR action and the deterioration of the gas turbine ***,EGR-IGV-FFC was inferior to IGV-FFC in improving the performance at loads below 50% for the H-Class *** results obtained in this paper could help guide the application of EGR-IGV-FFC to enhance the part-load performance of various classes of GTCC systems.

关键词： E/F/H-Class gas turbine combined cycle performance improvement part-load conditions exhaust gas recirculation inlet/variable guide vane

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Carbon nanotubes and hexagonal boron nitride nanosheets co-filled ethylene propylene diene monomer composites: Improved electrical property for cable accessory applications

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HIGH VOLTAGE 2024年第3期9卷 546-555页

作者： zhang, Tiandong Xu, Huiduo Dai, Chuanxian zhang, Changhai zhang, Yongquan chi, Qingguo Harbin Univ Sci & Technol Sch Elect & Elect Engn Harbin 150080 Peoples R China

Rubber-based composites based on ethylene propylene diene monomer (EPDM) with excellent non-linear electrical conductivity are preferred to serve as reinforced insulation in cable accessories, which can self-adaptively regulate electric field distribution and avoid electric field concentration due to the non-linear conductivity. The conductive carbon nanotubes (CNT) are filled into EPDM to improve the non-linear conductivity, while the insulating hexagonal boron nitride nanosheets (h-BN) are used to reconcile the electric breakdown strength. The results show that with the increase of CNT loading content, the non-linear conductivity of CNT/h-BN/EPDM composites becomes more prominent, accompanying the decrease of threshold field strength and increase of non-linear coefficient. However, the electric breakdown strength of CNT/h-BN/EPDM composites seriously deteriorates due to the increase of CNT content and temperature. By incorporating 1. wt.% h-BN into the composites, the reduction percentage of breakdown strength can be significantly lowered, which is 1..95% of neat EPDM and 1..74% of CNT/h-BN/EPDM composites at 70 & DEG;C, respectively. The COMSOL Multiphysics simulation results demonstrate that using the CNT/h-BN/EPDM composite as the reinforced insulation can eliminate the electric field concentration of the cable accessory as well as enable the cable accessory with good lightning shock resistance.

关键词： NONLINEAR CONDUCTIVITY

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The fast method and convergence analysis of the fractional magnetohydrodynamic coupled flow and heat transfer model for the generalized second-grade fluid

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Science china Mathematics 2024年第4期67卷 919-950页

作者： Xiaoqing chi Hui {1. Xiaoyun Jiang School of Mathematics and Statistics Shandong UniversityWeihai 264209China School of Mathematics Shandong UniversityJinan 250100China

In this paper,we first establish a new fractional magnetohydrodynamic(MHD)coupled flow and heat transfer model for a generalized second-grade *** coupled model consists of a fractional momentum equation and a heat conduction equation with a generalized form of Fourier *** second-order fractional backward difference formula is applied to the temporal discretization and the Legendre spectral method is used for the spatial *** fully discrete scheme is proved to be stable and convergent with an accuracy of O(τ^(2)+N-r),whereτis the time step-size and N is the polynomial *** reduce the memory requirements and computational cost,a fast method is developed,which is based on a globally uniform approximation of the trapezoidal rule for integrals on the real *** strict convergence of the numerical scheme with this fast method is *** present the results of several numerical experiments to verify the effectiveness of the proposed ***,we simulate the unsteady fractional MHD flow and heat transfer of the generalized second-grade fluid through a porous *** effects of the relevant parameters on the velocity and temperature are presented and analyzed in detail.

关键词： fractional MHD coupled flow and heat transfer model generalized second-grade fuid fast method convergence analysis numerical simulation

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Application of surfactant for improving leaching process of weathered crust elution-deposited rare earth ores

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Journal of Rare Earths 2024年第1期42卷 181-190,I0007页

作者： Fang Zhou Lisen zhang Zhiwei Wang Yixin zhang Ru'an chi Xiaoyan Wu Key Laboratory for Green Chemical Process of Ministry of Education Wuhan Institute of TechnologyWuhan430073China

Weathered crust elution-deposited rare earth ores(WREOs)in china are the main source of medium and heavy rare earths in the *** order to improve the seepage and the mass transfer of traditional ammonium salt leaching process of WREOs,surfactants were added in the ammonium sulfate leaching solution and the ammonium chloride leaching *** leaching kinetics,the mass transfer process,and the adhesion work reduction factor calculated from the interfacial properties were studied to reveal the strengthening mechanism of *** the presence of the tested five surfactants,cetyl trimethyl ammonium bromide(CTAB),dodecyl trimethyl ammonium bromide(DTAB),sodium dodecyl sulfate(SDS),sodium oleate and oleic acid,the permeability of WREOs is improved,the rare earth(RE)leaching efficiency increase and the impurity aluminum(Al)leaching efficiency decrease,indicating its promotional effect on the leaching process of ***,CTAB shows a better leaching enhancement,and the optimal addition dosage is 0.4 g/L for the two ammonium salt leaching agent *** kinetics analysis shows the internal diffusion controls model of RE and Al leaching process,and the leaching kinetics equations of RE and Al related to CTAB concentration were obtained for the two ammonium salt leaching *** to the chromatographic plate theory,the mass transfer efficiency of RE increases with the CTAB concentration increasing until 0.4 g/L,which confirms that the optimal CTAB addition is 0.4 g/*** adhesion work and adhesion work reduction factor indicate more favorable permeation as well as the leaching process.

关键词： Weathered crust elution-deposited rare earth ores Surfactant Kinetics Mass transfer

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Transient long-range distance measurement by a Vernier spectral interferometry

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Photonics Research 2024年第6期12卷 1107-1114页

作者： LIANG XU KUN WANG CHEN LIU WENYING CHEN chi {1. XINLIANG {1. Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Optics Valley Laboratory Wuhan 430074China

Rapid and long-range distance measurements are essential in various industrial and scientific applications,and among them,the dual-comb ranging system attracts great attention due to its high ***,the tem-poral asynchronous sampling results in the tradeoff between frame rate and ranging precision,and the non-ambiguity range(NAR)is also limited by the comb cycle,which hinders the further advancement of the dual-comb ranging *** this constraint,we introduce a Vernier spectral interferometry to improve the frame rate and NAR of the ranging ***,leveraging the dispersive time-stretch technology,the dual-comb interferometry becomes spectral ***,the asynchronous time step is unlimited,and the frame rate is improved to 1.0 ***,dual-wavelength bands are introduced to implement a Vernier spectral interferometry,whose NAR is enlarged from 1.5 m to 1.5 ***,this fast and long-range system also demonstrated high precision,with a 22.91.nm Allan deviation over 1.-ms averaging *** a result,the proposed Vernier spectral interferometry ranging system is promising for diverse applications that necessitate rapid and extensive distance measurement.

关键词： interferometry spectral system

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Autonomy Evaluation of Unmanned Systems Based on Task Models

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Machine Intelligence Research 2024年第5期21卷 815-830页

作者： Yi Zou Zehao Ni Xun Lei chi {1. Key Laboratory of Complex Aviation Simulation System Beijing100076China State Key Laboratory of Multimodal Artificial Intelligence Systems(MAIS) Institute of AutomationChinese Academy of Sciences(CASIA)Beijing100190China Hong Kong Institute of Science&Innovation Chinese Academy of Sciences(HKISI CAS)Hong Kong999077China

In this study,relevant work on autonomy evaluation(AE)in recent years was comprehensively reviewed and classified from the perspective of task models,and a closed-loop task models based theoretical framework for AE was *** main contributions of this study are as follows.1.A taxonomy for AE based on task models was introduced to classify current theories,methods and standards.2)The limitations of the current autonomous evaluation methods were addressed to provide a theoretical framework for quantitative evaluation based on task models,and evaluation metrics for each stage were proposed based on the AE theoretical framework.3)Qualitative analyses of the superiority of the proposed AE framework based on the closed-loop task models were *** study attempts to provide a reference for researchers and engineers in the autonomous unmanned systems field and inspire future development of AE.

关键词： Unmanned system(UMS) autonomy evaluation task models closed-loop task models kill chain

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The degradation pathways of contaminants by reactive oxygen species generated in the Fenton/Fenton-like systems

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chinese Chemical Letters 2024年第10期35卷 184-195页

作者： chi {1. Ning Ding Yuwei Pan Lichun Fu Ying {1. Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution College of Environmental Science and Engineering Nankai University Key Laboratory of Cleaner Production and Integrated Resource Utilization of china National Light Industry Beijing Technology and Business University College of Biology and the Environment Nanjing Forestry University School of Iron and Steel Soochow University Key Laboratory of Pollution Process and Environmental Criteria Ministry of Education College of Environmental Science and Engineering Nankai University

Reactive oxygen species （ROSs） in Fenton process are of great importance in treating contaminants in *** is crucial to understand their chemical properties,formation,and reaction mechanisms with *** review summarizes the reactive oxygen species in Fenton process,including hydroxyl radical （·OH）,superoxide radical (O2·-),singlet oxygen （1.2）,hydroperoxyl radical （HO2·）,and high-valent iron.·OH shows a trend to react with chemistry groups with abundant electrons through H-atom abstraction,radical adduct formation and single electron *** transfer is discovered to be an important pathway when1.2degrades organic ***-opening and β-scission are proposed to be the possible ways of1.2to certain *** abstraction,nucleophilic substitution,and single electron transfer are proposed to explain how O2·-degrade *** the conjugated acid of O2·-,radical adduct formation and H-atom abstraction are reported for the reaction mechanisms of hydroperoxyl ***-valent iron in Fenton,namely Fe（IV）,reacts with certain pollutants via single-or two-electron *** review is important for researchers to understand the ROSs produced in Fenton and how they react with pollutants.

关键词： Fenton High-valent iron Hydroperoxyl radical Hydroxyl radical Singlet oxygen Superoxide radical

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Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： chi {1. Rong Liu Jing-Yuan Liu Wen-Wei Jiang Key Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

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